This Study Demonstrates the disconnect between performance on the Cogscreen AE and performance in the flightdeck. https://lpba.org/Uploads/ConventionsEvents/Winter2019/190309%20-%20945am%20-%20John%20Hastings%20Powerpoint.pdf
and http://civilavmed.org/wp-content/uploads/2016/03/The-Real-World-Jack-Hastings.pdf
This shows that the FAA narrative is incorrect regarding a 100% correlation between Cogscreen performance and piloting ability and the link is weak at best.